首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   607篇
  免费   17篇
耳鼻咽喉   3篇
儿科学   1篇
妇产科学   9篇
基础医学   25篇
口腔科学   4篇
临床医学   214篇
内科学   197篇
皮肤病学   6篇
神经病学   32篇
特种医学   64篇
外科学   21篇
综合类   3篇
预防医学   27篇
眼科学   4篇
药学   12篇
肿瘤学   2篇
  2022年   8篇
  2021年   7篇
  2019年   3篇
  2018年   6篇
  2017年   5篇
  2016年   8篇
  2015年   9篇
  2014年   14篇
  2013年   21篇
  2012年   28篇
  2011年   37篇
  2010年   18篇
  2009年   15篇
  2008年   14篇
  2007年   21篇
  2006年   18篇
  2005年   21篇
  2004年   25篇
  2003年   25篇
  2002年   21篇
  2001年   26篇
  2000年   23篇
  1999年   20篇
  1998年   17篇
  1997年   26篇
  1996年   22篇
  1995年   20篇
  1994年   15篇
  1993年   8篇
  1992年   19篇
  1991年   10篇
  1990年   15篇
  1989年   4篇
  1988年   24篇
  1987年   8篇
  1986年   12篇
  1985年   13篇
  1984年   3篇
  1983年   5篇
  1982年   1篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1971年   1篇
  1969年   2篇
  1967年   1篇
  1965年   1篇
  1939年   1篇
排序方式: 共有624条查询结果,搜索用时 15 毫秒
571.
572.
573.
PURPOSE: Because limited audit/feedback of health status information has yielded mixed results, we evaluated the effects of a sustained program of audit/feedback on patient health and satisfaction. METHODS: We conducted a group-randomized effectiveness trial in which firms within Veterans Administration general internal medicine clinics served as units of randomization, intervention, and analysis. Respondents to a baseline health inventory were regularly mailed the 36-Item Short Form (SF-36) and, as relevant, questionnaires about six chronic conditions (ischemic heart disease, diabetes, chronic obstructive pulmonary disease, depression, alcohol use, and hypertension) and satisfaction with care. Data were reported to primary providers at individual patient visits and in aggregate during a 2-year period. RESULTS: Baseline forms were mailed to 34,050 patients; of the 22,413 respondents, 15,346 completed and returned follow-up surveys. Over the 2-year study, the difference between intervention and control groups (as measured by difference in average slope) was -0.26 (95% confidence interval [CI]: -0.79 to 0.27; P=0.28) for the SF-36 Physical Component Summary score and -0.53 (95% CI: -1.09 to 0.03; P=0.06) for the SF-36 Mental Component Summary score. No significant differences emerged after adjusting for deaths. There were no significant differences in condition-specific measures or satisfaction between groups after adjustment for provider type, panel size, and number of intervention visits, or after analysis of patients who completed all forms. CONCLUSION: An elaborate, sustained audit/feedback program of general and condition-specific measures of health/satisfaction did not improve outcomes. To be effective, such data probably should be incorporated into a comprehensive chronic disease management program.  相似文献   
574.
575.
In 1981, a large, double-blind, randomized trial was started in The Netherlands to evaluate the therapeutic effects of nifedipine and/or metoprolol in patients with unstable angina. This study has been called the Holland Interuniversity Nifedipine/metoprolol Trial (HINT) and required several hundred patients to establish potential therapeutic effects. From December 1982 to January 1984 the effects of nifedipine on left ventricular (LV) performance in a subgroup of 52 HINT patients were studied using radionuclide techniques. All patients (23 on nifedipine, 29 controls) underwent thallium-201 scintigraphy or radionuclide angiography just before and 48 h after the start of experimental medication. The radionuclide angiographic studies were also performed at 1 and 4 h after treatment. Nifedipine did not influence the incidence or disappearance of perfusion defects on the 48-h thallium images. No significant differences in overall LV ejection fraction (EF) were seen at any time between nifedipine-treated patients and controls. However, paired observations in 37 patients showed improvement of LVEF after 48 h in 8 patients on nifedipine and in only 1 control patient. Scintigraphic measurements on admission were not related to clinical outcome after 48 h. Concomitant administration of metoprolol did not influence LVEF in either group. It is concluded that nifedipine improves LVEF after 48 h in a subset of patients with unstable angina without affecting myocardial perfusion. This finding indicates that nifedipine has a predominant effect on afterload reduction in patients with unstable angina. However, early scintigraphic measurements had no significant predictive value for subsequent cardiac events.  相似文献   
576.
Almost without any exemption, new cardiac catheterization laboratories are entirely digital without 35 mm cinefilm as the storage medium. In addition, existing laboratories are increasingly converting to the digital world. Aside from the organizational aspects, this has significant implications for the daily diagnostic review process of the procedures, and for the quantitative analysis of selected frames by QCA. The DICOM standard has now been well accepted in the catheterization laboratories. In stead of mechanical cine projectors, a department must decide on so-called DICOM-Viewers or ‘digital Tagarno's’. In this paper the effects of DICOM on image quality and therefore on the visual interpretation of these images, as well as on QCA are discussed. Since the digital images can be enhanced, these look sharper than the conventional cinefilm images. However, edge enhancement has an effect on QCA, reason why the digital data must be stored in raw format. With the enormous amounts of digital data produced in a catheterization laboratory, image compression is of great importance. Currently, an international study is being carried out to determine which compression level is still acceptable from a visual interpretation and QCA point of view. Finally, the implications of the digital era on clinical trials are discussed. One of the important conclusions is that one should be encouraged not to switch from cinefilm to digital in the course of a trial, while a mixed population from the beginning is no problem, as long as the proper statistical calculations are carried out. In conclusion, despite the fact that there are still a number of items to be checked and possibly modified in the standard, the existing DICOM standard has succeeded in bringing widespread utilization of QCA in cardiac angiography closer than ever.  相似文献   
577.
OBJECTIVE: To describe ethnic differences in the risk of amputation in diabetic patients with diabetic nephropathy. RESEARCH DESIGN AND METHODS: A retrospective cohort study was conducted on a national cohort of diabetic patients who received primary care within the Veterans Affairs (VA) Health Care System. Hospitalizations for lower-limb amputations were established by ICD-9-CM procedure codes. Relative risk of amputation in diabetic patients with and without diabetic nephropathy was determined using Cox proportional hazard modeling for unadjusted and adjusted models. RESULTS: Of the 429,918 subjects identified with diabetes (mean age 64 +/- 11 years, 97.4% male), 3,289 individuals were determined to have had a lower-limb amputation during the study period. Compared with diabetic patients without amputations, amputees were on average older, more likely to belong to a minority group, and were more likely to have received treatment for more comorbid conditions. Asians were more likely to have toe amputations compared with whites or other ethnicities, while Native Americans were more likely to have below-the-knee amputations. Native Americans had the highest risk of amputation (RR 1.74, 95% CI 1.39-2.18), followed by African Americans (RR 1.41, 95% CI 1.34-1.48) and Hispanics (RR 1.28, 95% CI 1.20-1.38) compared with whites. The presence of diabetic nephropathy increased the risk of amputation threefold in all groups. Asian subjects with diabetes had the lowest adjusted relative risk of amputation (RR 0.31, 95% CI 0.19-0.50). CONCLUSIONS: Among diabetic patients, certain ethnic minority individuals have an increased risk of lower-extremity amputation compared with whites. Presence of diabetic nephropathy further increases this risk.  相似文献   
578.
A 57-year-old female underwent total ankle arthroplasty for post-traumatic arthrosis using the Agility Total Ankle System. The talar component was placed in varus malalignment. Her postoperative course was remarkable for 19 months of satisfactory function followed by the acute onset of intense pain and decreased range of motion. There was no history of trauma. After failing a short course of observation, revision surgery of the arthroplasty was performed. Operative findings revealed a complete fracture of the polyethylene. This report details the first case of such a complication and discusses the importance of component alignment in the prevention of polyethylene insert failure.  相似文献   
579.
BACKGROUND: Atrichia with papular lesions (APL) is a rare, autosomal recessive form of total alopecia in which mutations in the hairless (HR) gene have been shown to underlie the phenotype. OBJECTIVE: We suspect that APL is actually much more common than previously believed. We sought to investigate whether APL might also be found among patients in small families, particularly those giving a history of (1) normal hair at birth, which was shed and never regrew, and (2) "alopecia universalis" that is recalcitrant to any treatment. METHODS: We identified a small family of German origin in which 2 of 4 siblings were affected and gave this clinical history. Direct sequence analysis of the HR gene in the nuclear family was performed. RESULTS: Mutation analysis revealed distinct mutations on each allele of the HR gene. This is the first demonstration of compound heterozygous mutations underlying APL. CONCLUSION: These findings support the hypothesis that APL can exist in small nonconsanguineous families and may be masquerading clinically as alopecia universalis. Accurate discrimination between APL and alopecia universalis should prevent unnecessary treatment of patients affected with APL.  相似文献   
580.
Fenproporex is a sympathomimetic agent with a pharmacological profile similar to that of amphetamine. It is available in many countries throughout the world, but it is currently not available in the United States. Because of its stimulant effects, it has a great potential for abuse. To the best of our knowledge, there have been no literature reports of blood or serum concentrations found in therapeutic, toxic, or fatal cases. We report a case where fenproporex was a finding in the death of a young adult. Blood, urine, and gastric contents were analyzed. The following drug concentrations were found: 0.90 mg/L (inferior vena cava blood), 1.2 mg/L (urine), and 120 mg total (gastric) for fenproporex and 0.084 mg/L (inferior vena cava blood), 0.94 mg/L (urine), and 0.14 mg total (gastric) for amphetamine. In addition to the fenproporex, other medications detected and their blood concentrations found in this case were H diazepam (0.54 mg/L), nordiazepam (0.46 mg/L), diphenhydramine (0.12 mg/L), and gamma hydroxybutyric acid (GHB) (1100 mg/L).  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号